Some validations

validacoes.js

function isEmptyParam(param) {
    if (param || param.length > 0)
      return false;
    else
      return true;
  }
  
  function verifyMinCaracteres(min, str) {
    if (str.length >= min)
      return true;
    else
      return false;
  }
  
  function verifyMaxCaracteres(max, str) {
    if (str.length === max)
      return true;
    else
      return false;
  }
  
  function isInteger(num) {
    if (Number.isInteger(num))
      return true;
    else
      return false;
  }
  
  function isRealNumber(num) {
    if (!Number.isInteger(num) && isReal(num))
      return true;
    else
      return false;
  }
  
  function isReal(num) {
    return typeof num == 'number' && !isNaN(num);
  }


console.log(`100 is real number : ${isReal(100)}`);
console.log(`100.2334532322333 is real number: ${isRealNumber(100.2334532322333)}`);

console.log(`100 is intenger: ${isInteger(100)}`);
console.log(`100.122345 is intenger: ${isInteger(100.122345)}`);

console.log(`'Olá mundo!' has 10 characters: ${verifyMaxCaracteres(10, 'Olá mundo!')}`);
console.log(`'Hello' has at least 3 characters: ${verifyMinCaracteres(3, 'Hello')}`);
console.log(`'Oi' has at least 3 characters: ${verifyMinCaracteres(3, 'Oi')}`);

console.log(`'' is a empty string: ${isEmptyParam('')}`);
console.log(`'Olá mundo!' is a empty string: ${isEmptyParam('Olá mundo!')}`);
console.log(`100 is a empty param: ${isEmptyParam(100)}`);
console.log(`null is a empty param: ${isEmptyParam(null)}`);
console.log(`undefined is a empty param: ${isEmptyParam()}`);